1. Field of the Invention
The present invention relates to a light source module, and more particularly, to a backlight module.
2. Description of Related Art
Referring to FIG. 1, a conventional backlight module 100 comprises four cathode cold fluorescent lamps (CCFL) 110, four lamp sockets 120 (only two of the lamp sockets are shown in FIG. 1), two lamp reflectors 130, a light guide plate 140 and a metal back plate 150. Each two of the CCFLs 110 are arranged in the corresponding lamp reflector 130, respectively. The lamp sockets 120 are arranged at the high voltage end and low voltage end of the CCFLs 110, and the CCFLs 110 and the lamp sockets 120 are surrounded by the lamp reflectors 130 and the light guide plate 140. Each of the lamp reflectors 130 comprises a metal substrate 132 and a reflective material layer 134. The reflective material layer 134 is disposed on the metal substrate 132 between the metal substrate 132 and the lamp sockets 120. The edge of the metal substrate 132 overlaps with the edge of the reflective material layer 134. In addition, the lamp reflectors 130 and the light guide plate 140 are disposed on the metal back plate 150.
The reflective material layer 134 is suitable for reflecting light (not shown) emitted from the CCFLs 110 toward the light guide plate 140, and the light guide plate 140 is suitable for transforming the light into a surface light source (not shown). When the CCFLs 110 emit light, waste thermal energy is also generated simultaneously, particularly at the high voltage end and the low voltage end of the CCFLs 110. The waste thermal energy is conducted to the metal substrate 132 through the lamp sockets 120 and the reflective material layer 134 for heat dissipation. Generally speaking, the area of the metal substrate 132 is smaller, such that the heat dissipation efficiency of the metal substrate 132 is limited. Accordingly, the waste thermal energy is conducted to the outside through the metal back plate 150.
However, the metal substrate 132 is not tightly contacted with the metal back plate 150 due to the manufacturing and assembly error between the metal substrate 132 and the metal back plate 150. The waste thermal energy is not likely to be conducted from the metal substrate 132 to the metal back plate 150, and it causes a poor heat dissipation efficiency of the backlight module 100. Further, a printed circuit board (not shown) is usually arranged under the metal back plate 150 for driving a liquid crystal display (LCD) panel (not shown), and therefore there is a need to arrange a plurality of insulating materials between the metal back plate 150 and the printed circuit board to prevent a short circuit therebetween. Hence, this causes the difficulty in design and a higher manufacturing cost of the backlight module 100.